1. Technical Field of the Invention
The present invention relates to a Liquid Crystal Display (LCD) driver that provides adjustable contrast independently of the multiplexing method.
2. Description of Related Art
LIQUID CRYSTAL DISPLAYS (LCDs) are used for displaying messages. There are various methods to drive the LCD display. One method uses inbuilt hardware drivers/controllers to control the display of characters/graphics on the LCD. Such LCD modules are easier to interface but are expensive due to the inbuilt hardware drivers/controllers. Another method to drive an LCD display is through a dedicated Microcontroller which has an inbuilt hardware LCD driver to control the LCD display as well as the Contrast. Such a method is also relatively expensive.
U.S. Pat. No. 4,385,294 describes an LCD display controller in which the LCD display is controlled by means of dedicated display drive circuitry. However, this display drive circuitry fails to work if the RMS voltage output of the circuitry is less than the LCD operating voltage. This arrangement is also relatively expensive to use.
There is accordingly a need to provide an improved and cost effective system for driving an LCD display and providing adjustable contrast independently of multiplexing requirements. Preferably, this system would make use of minimal hardware and thus provide a cost effective solution.